Update IP address on both PropertyChanged and LostFocus

Behaviors/UpdateSourceOnLostFocusBehavior.cs

@@ -0,0 +1,32 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using Microsoft.Xaml.Behaviors;
+
+namespace fs2ff.Behaviors
+{
+    public class UpdateSourceOnLostFocusBehavior : Behavior<TextBox>
+    {
+        protected override void OnAttached()
+        {
+            base.OnAttached();
+
+            if (AssociatedObject != null)
+                AssociatedObject.LostFocus += AssociatedObject_LostFocus;
+        }
+
+        protected override void OnDetaching()
+        {
+            if (AssociatedObject != null)
+                AssociatedObject.LostFocus -= AssociatedObject_LostFocus;
+
+            base.OnDetaching();
+        }
+
+        private static void AssociatedObject_LostFocus(object sender, RoutedEventArgs e)
+        {
+            if (sender is TextBox textBox)
+                BindingOperations.GetBindingExpression(textBox, TextBox.TextProperty)?.UpdateSource();
+        }
+    }
+}

MainWindow.xaml

@@ -5,7 +5,7 @@
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:ui="http://schemas.modernwpf.com/2019"
         xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
-        xmlns:behaviors="clr-namespace:fs2ff.Behaviors"
+        xmlns:b="clr-namespace:fs2ff.Behaviors"
         xmlns:c="clr-namespace:fs2ff.Converters"
         ui:WindowHelper.UseModernWindowStyle="True"
         mc:Ignorable="d"
@@ -86,12 +86,13 @@
                     Text="{
                         Binding IpAddress, Mode=TwoWay,
                         Converter={c:IpAddressToStringConverter},
-                        UpdateSourceTrigger=LostFocus}"
+                        UpdateSourceTrigger=PropertyChanged, Delay=5000}"
                     Template="{StaticResource WatermarkTextBoxTemplate}"
                     Tag="255.255.255.255"
                     Margin="0,10,0,0">
                     <i:Interaction.Behaviors>
-                        <behaviors:MoveFocusOnEnterBehavior />
+                        <b:MoveFocusOnEnterBehavior />
+                        <b:UpdateSourceOnLostFocusBehavior />
                     </i:Interaction.Behaviors>
                 </TextBox>
                 <Label